Junction-box.



No. 7l6,643. Patented Dec. 23, I902.

C. G. M. MILLER & F. D. MASTERSON.

JUNCTION BOX.

(AppHca-tion filed Mar. 2. 1901.

(No Model.)

witnesses; J f

UNTTED STATES PATENT OFFICE.

CARL G. M. MILLER, OF NEWTON, MASSACHUSETTS, AND FRANK D. MAS- TERSON, OF BOSTON, MASSACHUSETTS, ASSIGNORS TO CHASE-SHAWMUT COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION OF MAINE.

JUNCTION BOX.

SPECIFICATION formingpart of Letters Patent No. 716,643, dated December 23, 1902.

Application filed March 2,1901.

To all whom, it may concern:

Be it known that we, CARL G. M. MILLER, of Newton, in the county of Middlesex, and FRANK D. .MASTERSON, of Boston, in the county of Suffolk, State of Massachusetts,

have invented an Improvement in Junction- Boxes, of which the following description, in connection with the accompanying drawings, is a specification, like letters on the drawings representing like parts.

This invention relates to junction-boxes for electric-wiring purposes, and has for its object to improve the construction of the same in several particulars, better adapting it for the purposes for which it is intended; and the invention consists in details of construction as will be hereinafter specifically described and claimed.

Figure 1 shows in plan view a junction-box 2o embodying this invention. Fig. 2 is a vertical section of the same, taken on the dotted line 2 2. Fig. 3 is an under side View of the junction-box, and Fig. 4 is a detail showing a portion of the box in side elevation.

The junction-box is made as a casting, of iron or any other suitable material, and consists of a circular or other-shaped shell having an end wall a and a side wall Z). The end wall a has recesses formed in the casting on both of its sides or faces, there being a number of such recesses a herein shown as formed in its outer side or face, and a corresponding number of recesses a formed in its inner side or face opposite the aforesaid recesses a WVithin the boundaries of said recesses the material is very thin, as indicated by dotted lines, Fig. 2, and consequently may be easily broken out or knocked out when desired, and the pieces, web, or films so knocked out correspond in area to the openings produced by their removal. By disposing said thin portions at the bottoms of the recesses the liability of breaking the box when breaking out the holes is reduced to the minimum, and a cleaner hole may be broken, as the metal is less liable to chip off at the edges, and, fur thermore, visual indications are provided on the outside of the wall which indicate to the workmen just where to strike the blow. In 50 the side wall Z) of the shell similar recesses Serial No. 49,571. (No model.)

are also provided, as many as may be desired, being located both inside and outside of the wall, and like thin portions, called knockout portions, are consequently provided.

By referring to Fig. 2, b I) represent the recesses in the opposite sides or faces of the wall, and 17 represents the thin portion or knock-out portion.

The side wall I) is oftentimes made circular, as shown in the drawings, and in such case it has been difflcult to secure a coupling thereto, for the reason that the seats upon the opposite sides or faces of said wall against which the members of said coupling abut are curved; but herein the wall is formed with flat portions or faces, both inside and out, surrounding the several recesses 1) b and by so forming said side wall it will be seen that flat seats are provided,against which the members of the coupling will abut, which insures a better joint.

0 represents one of the fiat faces which is provided inside of the wall 5, it extending from top to bottom of the wall, and a represents one of the flat faces provided outside of the Wall.

It is furthermore apparent that by providing flat faces or seats, as herein shown, the side wall I) will be made thicker at said points, and such increase in thickness will be suffi- 8o cient to enable a tap to operate and tap a hole, as 2, for a screw without the necessity of providing the shell with inwardly-projecting ears, which have heretofore been required for this purpose.

The coupling herein shown comprises a union d and a screw-threaded nipple d,and by referring to Fig. 2 it will be seen that said parts bear flat against the flat seats provided for them. I

Heretofore the side wall has been made circular and a recess has been cast in its inner side, but in such case the bottom of the recess has been curved to correspond with the curvature of the said wall, and as a result a 5 piece having a curved face must be broken out, and in practice it is difficult to break out such a curved piece without breaking the box. Herein the bottom of the recess is formed flat instead of curved, as shown in Fig. 2, and too hence can be struck a severe blow with a peen or other suitable implement and effectively broken out without breaking the box. Thus the provision of fiat knock-out portions in a curved side wall is one of the important features of our invention.

We claim 1. In a junction-box, a shell or case having a curved side wall formed with recesses both inside and outside of its walls, disposed opposite each other and leaving a thin flat knock-out portion, substantially as described.

2. In a junction-box, a shell or case having a curved side wall formed with recesses and with flat portions surrounding said recesses which provide fiat seats against which the members of the coupling abut, substantially as described.

3. In a junction-box, a shell or case having a curved side wall formed with a recess and with a thin flat knock-out portion at the bottom of said recess, substantially as described.

4. In a junction-box, a shell or case having a curved side wall formed upon its outer face with flat bearing-surfaces below the surface of which are located flat knock-out portions, substantially as described.

5. In a junction-box, a shell or case having a curved side wall formed with one or more thickened places including flat outer bearingfaces and flat knock-out portions, substantially as described.

6.' In a junction-box, a shell or case having a curved side wall formed with recesses both inside and out, and with flat portions surrounding said recesses both inside and out which provide flat seats against which the members of the coupling abut, substantially as described.

7. A knock-out box made in one piece and having a curved flange formed with flat knock-out webs or films substantially corresponding in area to the openings produced by their removal.

8. A circular knock-out box made in one piece and having a curved flange formed with flat knock-out webs or films set below its outer surface and substantially correspond- 

